NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair value of financial instruments and Inventories (Details) - item	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
FAIR VALUE OF FINANCIAL INSTRUMENTS
Number of financial instruments transferred from Level 1 to Level 2	0
Number of financial instruments transferred from Level 2 to Level 1	0
INVENTORIES
Percentage of total LIFO inventory	71.00%	65.00%
Maximum inventory reserve as a percentage of FIFO inventory value	6.80%	6.80%